Conventional store suspension and release units for aircraft comprise sway braces used to hold the store steady during carriage in flight, and separate gas-powered pistons which push the store away from the aircraft at the moment of release, so that the store is ejected out of the aircraft slipstream in a controlled manner, along the correct trajectory, without risk of colliding with the aircraft. The size and mass of conventional stores makes such power assisted ejection necessary. The electrical interface between such suspension and release units and the store for arming, target programming and similar functions is provided by an umbilical cable with a releasable electrical connector at one end attached to the store. This allows the store to be mechanically attached to the suspension and release unit before the electrical connection is made up, making the relatively large and heavy conventional stores easier to load. However, such cables can cause additional drag during separation of the store from the aircraft, necessitating still higher ejection forces. Powered ejection systems and umbilical connector cables have therefore been found necessary for conventional stores, but are complex and expensive in both hardware and maintenance costs.